Demolition system



May 15, 1956 Filed March 26, 1945 E- M. BROWN ET AL DEMOLITION SYSTEM 5Sheets-Sheet 1 56 .Mrown/ CJLee SR. Gilford May 152, 1956 E. M. BROWN ETAL 2,745,369

DEMOLITION SYSTEM Filed March 26, 1945 3 Sheets-Sheet 2 EQ; 4. E@ 5.

EM Brown i 2 Lee ,S R. (i lford j@ (CML/Mw@ May 15, 1956 E. M. BROWN ETAL 2,745,369

DEMOLITION SYSTEM Filed March 26, 1945 5 Sheets-She 5 |04 1 HMAINCHARGE| 1| l nited States Patent DEMOLITION SYSTEM Ellis M. Brown,Charles B. Lee, and `Saul R. Gilford, United States Navy, Washington, D.C.

Application March 26, 1945, Serial No. 584,996

14 Claims. (Cl. 114-21) (Granted under Title 35, U. S. Code (1952), sec.266) This invention relates generally to a demolition system in which avessel having a main explosive charge and a plurality of auxiliary orscuttling charges is self-propelled under control of the operator of aradio transmitter remotely situated with respect to the vessel to apoint at which it may be desired to: fire the scuttling charges therebyto sink the vessel and, thereafter, within a predetermined period oftime, to tire the main charge for the purpose of clearing mines andother obstructions from an area in which it is desired to establish abeachhead; or to lire the main charge to destroy enemy docks and vesselsor the like Without tiring the scuttling charges; or merely to tire theauxiliary charges to sink the vessel for the purpose of preventing itfrom falling into enemy hands or for the purpose of obstructing theentrance to a harbor; these operations also being accomplishedselectively under remote control of the operator of the transmitter.

More specifically, the present invention contemplates the provision of aplurality of control circuits for firing the main charge, for tiring thescuttling and main charges in predetermined time spaced relation, or fortiring the scuttling charges selectively under remote control of thetransmitter, an additional control circuit, also under control of thetransmitter, being provided for arming the foregoing circuits andremoving an obstruction between the detonator and booster chargeassociated with the main charge, as the vessel approaches its objective.

Each of the control circuits comprises a rotary timing device having aplurality of cams and contacts adapted to be controlled thereby in amanner to eifect positively the arming of the control circuits, tiringof the scuttling and main charges in the desired sequence, or tiring ofthe main charge or the scuttling charges, whichever the case may be, andto cut olf the ignition to the propelling engine for the vesselsimultaneously with the tiring of the scuttling charges.

For the reason that radio waves are ineffective to control remotely theoperation of devices disposed beneath the surface of a body of water,the aforedescribed tiring of the main charge in predetermined timedelayed relation to the tiring of the scuttling charges is providedunder control of one of the rotary timing devices after operationthereof is initiated by remote control. Therefore, to insure that thetiming device will cause ring of the main charge only after the vesselhas been submerged to a depth beneath the surface of the water at whichthe desired explosive damage may be eiected, the timing devicenecessarily is designed so as to be well adapted to prevent prematureclosing of the main charge tiring circuit in response to shocksresulting from the explosion of the scuttling charges. Moreover, thetiming devices of the several control circuits similarly are designed toprevent spurious operation of the circuits in response to vibration ofthe vessel incident to operation thereof.

An object of the present invention, therefore, is to provide a pluralityof control circuits for selectively ring a plurality of scuttlingcharges and/or main explosive charge of a demolition unit under controlof a radio transmitter remotely situated with respect to the unit.

Another object of the invention is to provide a plurality of controlcircuits for a self-propelled demolition unit in which one of thecircuits may be employed to arm the other circuits as the unitapproaches its objective and in which the scuttling and main charges maybe fired independently of each other or in predetermined time spacedrelation selectively under control of the other of said circuits.

Another object is the provision of an arming control circuit for aremotely controlled demolition unit in which means under control of thearming circuit are employed to remove an obstruction between thedetonator and booster charge associated with the main charge.

Another object resides in the provision of a control circuit for aself-propelled demolition unit having a plurality `of scuttling chargesin which a timing means is employed to re the scuttling charges and todisable the propelling means of the unit simultaneously.

An additional object of the invention is the provision of new andimproved rotary timing and circuit closing means adapted to avoidpremature or accidental closure of circuits controlled thereby inresponse to shocks resulting from explosion or vibration received fromassociated apparatus.

Still other objects and advantages of the invention not specifically setforth hereinabove are those implied from or inherent in the novelconstruction, combination and arrangement of parts as will become moreclearly apparent as the description proceeds, reference being had to theaccompanying drawings wherein:

Fig. l is a diagrammatic View illustrating the arrangement of theseveral parts comprising a demolition vessel or unit suitable for usewith the control circuits of the present invention;

Fig. 2 is a side elevation of a rotary timing device employed in thecontrol circuits of the invention;

Fig. 3 is a top plan view of the rotary timing device shown in Fig. 2;

Fig. 4 is an-enlarged sectional view of the rotary timing device as seenalong the line 4 4 of Fig. 3;

Fig. 5 is a sectional view of the timing device taken along the line 5 5of Fig. 4;

Fig. 6 is a sectional View taken substantially along the line 6-6 ofFig. 4;

Fig. 7 is a detailed view in elevation of one of the cam membersemployed in each of the timing devices;

and

Fig. 8 is a diagrammatic view of an electrical system suitable for usewith the demolition unit of Fig. l.

Referring now to the drawings for a more complete understand of theinvention, and more particularly to Fig. 1 thereof, the numeral 10generally designates a vessel suitable for use as a self-propelleddemolition unit, the vessel having an internal combustion engine li fordriving the usual propeller 12 of the vessel. Operation of the engine isunder control of a radio receiver 13 which in turn is automaticallycontrolled by a radio transmitter (not shown), remotely situated withrespect to the vessel, the receiver being adapted to regulateautomatically the speed control 14 of the engine at the will of thetransmitter operator. The radio receiver also is adapted automaticallyto operate a gyro steering control 15 which in turn is arranged tocontrol the usual rudder 16 of the vessel, thereby to direct the vesselin .a desired path of travel also at the will of the operator supportingthe shaft 31 at the ends thereof.

of the radio transmitter. The radio receiver further is adapted, as willappear more fully hereinafter, automatically to operate an explosivecontro-l 17 including a plurality of timing control circuits for firingselectively a plurality of scuttling charges 18 which are disposed invarious positions about the vessel such as most advantageously to causescuttling or sinking of the vessel when the charges are tired and.simultaneously, for interrupting the engine ignition circuit, thereby todisable the propelling mechanism of the vessel, and/or to tire a maincharge 19 adapted to destroy the vessel and all other deterrents tomilitary operations in the vicinity of the vessel when the main chargeis tired. l

Referring now to Figs. 2 through 7 in which a rotary timing deviceemployed in each of the aforementioned control circuits is disclosed, itwill be seen that the timing unit comprises a base 21 upon which auni-directional motor 22 of any type suitable for the purpose is mountedas by a support 23 in any convenient manner. The motor is preferably ofa type in which an armature is caused to rotate in the field of apermanent magnet when current is supplied to the armature by way ofbrushes 20 to which conductors may be secured in the usual manner. Themotor is arranged to drive a gear reduction unit 24 preferably through aflexible coupling 25 adapted to take up any misalignment of the shafts26 and 27 of the motor and reduction unit respectively. the reductionunit also being supported on the `base 21 in any convenient manner. Apinion 28 carried by the output shaft (not shown) of the reduction unit24 drives a gear 29 secured for. rotation with a countershaft 31 whichis mounted for rotation in a suitable bracket or support 32 havingupstanding spaced portions 33 for The remaining portion of the support32 preferably is boxshaped to provide a rigid structure for the supportof a pair of switch banks 34 and 35, to be described in greater detailhereinafter. Support 32 conveniently may be secured to the base as by aplurality of screws 36.

Referring now to Fig. 5, it will be seenl that switch bank, or contactbank 34 comprises a pair of contact springs 37 and 38 and a plurality ofinsulation spacers 39 which are secured to the support 32 by a. pair ofscrews 41, the insulation spacers or strips serving to insulate thecontact springs 37 and 38 from each other and from the screws 41 andsupport 32. Contact springs 37 and 38 comprise terminal strips 42 and 43respectively to which suitable conductors may be secured andV furthercomprise upwardly extending spring portions which terminate in contacts44 and 45 respectively, the spring portions serving to urge the contactsyieldably into en-l gagement with each other. The contacts normally aredisengaged from each other however, by means of a segmented annular cam46 which is interposed between contact springs 37 and 38. Cam 46preferably is formed integrally with and disposed about the periphery ofa hub 47, these parts comprising a cam member generally designated 48and preferably formed of any suitable insulating material. Cam 48 isfixed to or suitably formed with a sleeve member 49 having an enlargedshoulder 51 for cooperation with a clamping member 52 which is adaptedto be secured to the shoulder 51 by screws 53 in a manner to clamp thesleeve member 49 to the shaft 31 so as to provide angular adjustments ofthe cam member 48 with respect to the shaft, thereby to space the openportion of cam 46 with respect to contact springs 37 and 38 wherebyengagement of the contact springs as the open portion of the cam movesinto alignment therewith may be delayed for predetermined intervals oftime after operation of motor 22 is initiated. For this purpose thearrangement of motor 22 and gear reduction 24 is such that the motor iscaused to make a relatively great number of revolutions to move the cam46 through one revolution whereby a suitable interval of time isrequired to rotate the cam through one revolution. The arrangement ofthe driving connections between the motor22 and the shaft 31 is such asto cause cam 46 to move in the direction of arrow 54, Fig. 5, theleading end of cam 46 being formed to a knife edge at 55 to facilitatedisengagement of contact springs 37 and 38 in the event that it isdesired to ro tate the cam through more than one revolution.

From the afo-redescrihed arrangementy of contact springs 37 and 38 andthe associatedtcarn 46 therefor in which the cam is interposed betweenthe contact springs except when the open portion of the cam moves intoalignment with the springs, it should now be apparent that anarrangement has been provided whereby disengagement ofthe contacts ispositively maintained except at such time as closure thereof is desired.Accordingly, the arrangement is well adapted to prevent premature oraccidental lclosing of the contacts in response to suddent shocks orvibration..

Switch or contact bank 35 similarly comprises contact springs 56 through59 and a plurality of insulating spacers 61fand suitable backstopelements 62 which are adapted to be secured to the support 32 in stackedrelation thereon, substantially as shown, by means of screws 63, contactelements 56 and 59 having suitable terminal strips 64 through 67respectively, to which conductors may be secured in the usual manner.Contact spring 59 carries a follower element 68 for engagement with aperipheral cam 69, element 68 normally being seated within the notchedportion 71 of cam 69 and adapted to be moved out of the notched portionas the cam rotates, thereby causing contact spring 59,to move intoengagement with contact spring 58 which in turn causes contact spring 57to close contact spring 56 by way of transfer element 72 interposedbetween contact springs 57 and 58.

Cam 69 preferably is formed integrally with a hub portion 73, theseparts comprising a cam member gcnerally'designated 74 and formed of ,anyinsulating material suitable for the purpose. Cam member 74 isadjustably secured to shaft 31 by means of a clamping arrangement 75which may be identical to the clamping arrangement including parts 49through S3 employed with cam member 48 whereby the notched portion 71 ofcam member 74 may be adjusted with respect to follower 68 in order toplace the follower in seated relation within the notch. A spacer member70 preferably is secured to shaft 31 between camy members 4S andf74thereon for'the purpose of preventing axial displacement of the camswith respect to the contact banks individual thereto in response toshock or vibration received from apparatus associated therewith.-

Referring now to Fig. 8 Ain which the electrical system for thedemolition vessel 10 is disclosed, ,it will be seen that the radioreceiver 13 comprises a pair of input terminals 76 and 77 of whichterminal 77 is grounded and terminal 76 is connected to a suitableantenna 78. The radio receiver includes suitable mechanism adapted to becontrolled by signals received from the radio transmitter in response tothe operation of various controls thereof, thereby to apply potential.selectively between a grounded terminal 79 and any one of terminals 81through 84 at the output end of the radio receiver.

As the demolition unit approaches its objective, the radio transmitteris operated to apply potential between terminals 79 and 8,1 of the radioreceiver to initiate 'operation of the arming control circuit, generallydesignated A, of the unit. This is accomplished by operating relay 85 ofthe arming circuit by way of terminal 81, conductor 86, the winding ofrelay 85, and thence to ground potential at terminal 79. As the relay 85is operated,` potential from battery 87 is applied to the armature ofmotor 22 of the arming control circuit by way of battery 87, conductorv88, armature 89 and make contact of relay 85, armature 91 and breai'`contact of relay 92, armature of motor 22, and vthence by way of groundpotential to the opposite side of battery 87. As motor 22 operates, alocking circuit therefor is completed from battery 93 by way of contactsprings 56 and 57k of switch bank 35 of arming circuit A, conductor 94,and thence through the armature of motor 22 to ground potential at theother side of battery 93.

Contact springs 58 and 59 of switch bank 35 of arming circuit A also areclosed to apply potential from battery 95 to a solenoid 96 of an armingdevice generally designated 97 by way of conductor 98, contact springs58 and 59 of switch bank 35 of arming circuit A, conductor 99, solenoid96, and thence by way of conductor 101 to the other side of battery 95.As solenoid 96 operates, a spring biased plunger 102 thereof isretracted to release a spring biased obstructing member 103 to permitsufficient movement of the member to bring a passageway 104 therein intoalignment with a passageway interconnecting an electroresponsivedetonator 105 and a booster charge 106 for the main charge 19, wherebyan operative firing connection is provided between the detonator andbooster charge.

When motor 22 of arming circuit A has driven cam 69 through 180,follower 68 of switch bank 35 moves into an additional notch 71Aprovided on cam 69, thereby to disengage contacts 56 and S7 andinterrupt the aforedescribed locking circuit to the motor. Theadjustment of cam 46 for the purpose of the arming circuit A is suchthat the open portion of cam 46 is brought into alignment with contactsprings 37 and 38 of switch bank 34 as follower 68 moves into notch 71Aon cam 69. As contact springs 37 and 38 close, a circuit is completedfrom battery 107 for operating relay 92 by way of contact springs 37 and38, conductor 10S, winding of relay 92 andl thence to ground potentialon the opposite side of battery 107. As relay 92 operates, armature 91disengages the break contact thereof to interrupt the circuit heretoforetraced, for operating the motor 22 of arming circuit A by operation ofrelay 85 as potential is applied between terminals 79 and 81 of thereceiver 14, thereby to prevent inadvertent operation of the armingcircuit and resultant disarming of the demolition unit after armingthereof, or to prevent disarming of the unit by enemy operations.

Potential on conductor 108 from battery 107, as will appear ingreaterdetail hereinafter, also is utilized to arm circuits B, C and Dwhereby these circuits are operated upon initiation of operation thereofby the radio receiver.

Before connecting the aforedescribed arming circuit to the arming device97 upon assembling the various parts of the demolition system on thevessel 10, various precautionary steps. are taken to insure that cam 46of arming circuit A is not in a position in which the open portionthereof permits closure of contact springs 37 and 38, therebyprematurely to arm control circuits B, C and D, as pointed outhereinabove. In the event that contact springs 37 and 38 are closed atsuch time, this condition is indicated visually by means of a lamp 109which is connected in series with battery 107 and contact springs 37 and38 and, therefore, is lighted when the contacts are closed. In the eventthat the lamp is lighted, a reset switch 110 is provided for initiatingoperation of y motor 22 of arming circuit A to drive cams 46 and 69thereof through 180 to place the arming control circuit A in an unarmedcondition. This is accomplished by applying potential of battery 107 tothe motor by way of contact springs 37 and 38, conductor 108, switch110, armature of motor 22, and thence to ground potential at the otherside of battery 107, this circuit beingA interrupted as contact springs37 and 38 become disengaged and further movement of the motor beingprovided by means of the locking circuit therefor, heretofore traced.

if it is desired to re the scuttling charges and main charge in sequencewhen the demolition unit has reached its objective, a control isoperated at the radio trans'- mitter which causes potential to beapplied between terminals 79 and 83 of thc radio receiver, thereby tooperate relay 111 of the scuttling and main control circuit B by way ofterminal 83, conductor 112, and thence by way of winding of relay 111 toground potential at terminal 79. As relay 111 operates, potential frombattery 107 is applied to motor 22 of control circuit B by way ofconductor 108, armature 114 and make contact of relay 111, and thence byway of armature of motor 22 to ground potential at the other side ofbattery 107. As the operation of this motor is initiated, a lockingcircuit therefor is completed from battery 115 by way of contact springs56 and 57 of control circuit B, conductor 116, and thence by way ofarmature of the motor to ground potential at battery 11S, this lockingoperation being identical with that described in connection with thelocking circuit for motor 22 of arming control circuit A. Contactsprings 58 and 59 of control circuit B also close to apply potentialfrom battery 115 to motor 22 of the scuttling charge control circuit Dby way of contact springs 58 and 59 of circuit B, conductor 117, andthence by way of the armature of motor 22 of control circuit D to theground potential at the other side of battery 115. As the operation ofmotor 22 of circuit D is initiated, break contacts 118 and 119controlled by cam 69 of control circuit D are disengaged to interruptthe ignition circuit to engine 11 of vessel 10, thereby to stop thepropulsion of the vessel as it reaches its objective.

Cam 46 of control circuit D is adjusted such that the open portion ofthe cam moves into alignment with contact springs 37 and 38 associatedtherewith within a relatively short period of time such, for example, as5 seconds, thereby to close the contacts and apply potential frombattery 121 to the electroresponsive detonators 122 associated .with thescuttling charges by way of contact springs 37 and 38 of circuit D,conductor 123, detonators 122 in parallel and thence by way of conductor124 to the other side of battery 121. As the detonators 122 are fired,the scuttling charges are red in turn, thereby to scuttle the Vessel.Within a relatively long period of time thereafter, suliicient toprovide for the sinking of the vessel to a suitable depth ofsubniergence Within the water, such, for example, as seconds, the openportion of cam 46 of control circuit B moves into alignment with contactsprings 37 and 38 associated therewith, thereby to close the contactsand apply potential from battery 107 to detonator 105 associated withthe main charge 19 by way of conductor 108, contact springs 37 and 38 ofcircuit B, conductor 12S, and thence by way of detonator to groundpotential at the other side of battery 107. As detonator 105 is fired,booster charge 106 and the main charge 119 are fired in sequence,thereby to destroy the vessel and to clear the vicinity thereof of alldeterrents to military operations.

Alf it is desired to destroy an enemy vessel, docks or the like, or toprevent the demolition unit from falling into the hands of the enemy,the main charge may be red without firing the scuttling charges. This isaccomplished by operating a control at the radio transmitter whichapplies potential between terminals 79 and 82 of the radio receiver 13,thereby to operate relay 126 of the main charge control circuit C by wayof terminal 82, conductor 127, and thence by way of the winding of relay126 to ground potential at terminal 79. As relay 126 operates, a circuitis completed for initiating operation of motor 22 of control circuit Cby way of potential of battery 107 on conductor 108, armature 128 andmake contact of relay 126, and thence by way of armature of the motor toground potential at battery 107. As the operation of motor 22 ofcircuitfC is initiated, a locking circuit therefor is completed frombattery 129 by way of contact springs 58 and 59 of circuit C, and aconductor 131, to the motor thereof in the same manner as accomplishedfor motors 22 of control circuits A and B.

kanamnese Cam 46 of control circuit C is adjusted such that the openportion of the cam is moved into alignment with contact springs 37 and38 associated therewith within a relatively short period of time such,for example, as five seconds, thereby to close these contact springs andcornplete a circuit from battery 107 to detonator 105 associated withmain charge 19 by way of conductor 108, contact springs 3S and 37 ofcontrol circuit C, conductor 125, and thence by way of detonator 105 tothe ground potential at battery 107, thus causing the detonator 105 andthe main charge thereafter to be fired, as pointed out hereinabove.

lf it is desired merely to scuttle the vessel without firing the maincharge for the purpose of preventing the vessel from falling into thehands of the enemy or to obstruct the entrance to a harbor, a control isoperated at the radio transmitter which causes potential to be appliedbetween terminals 79 and 84 of the radio receiver, thereby to operaterelay 132 of control circuit B by way of terminal 84, conductor 133, andthence by way of winding of relay 132 to ground potential at terminal79. As relay 132 operates, potential on conductor 108 is applied by Wayof armature 134 and make contact of relay 132 to motor 22 of controlcircuit D, thereby to initiate the operation of the motor. As operationof the motor is initiated, a locking circuit therefor from battery 135`is established by way of contact springs 56 and 57 of control circuit Dand conductor 117 in the same manner as for the motors of controlcircuits A, B and C. As the operation of the motor is initiated,

the ignition circuit for the engine of vessel 10 is interrupted, andwithin five seconds thereafter, detonators 122 are tired to fire thescuttling charges, as previously described.

It will be obvious that, if desired, a singlebattery may be employed inplace of the several batteries 87, 93, 107, 115, 129 and 135 disclosedfor facilitating the description of the control circuits. Battery 121however, preferably is the vessels battery or a suitable section thereofto insure ample energization of detonators 122 associated with thescuttling charges.

' From the foregoing it should now be 'apparent thatl a plurality ofcontrol circuits and. rotary timing means therefor have been providedwhich are well adapted toV United States of America for governmentalpurposes n without payment of any royalties thereon or therefor.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

l. In a demolition unit adapted to be self-propelled to its objectiveand adapted to iire scuttling `and main explosive charges carriedthereby under remote control of an operator of the unit, the combinationof means under control of the operator of the unit for firing thescuttling and main explosive charges in predetermined sequence when theunit reaches its objective, and means controlled by said tiring meansfor disabling the propelling means of the unit and thereafter invariablytiring the scuttling charges.

2. In a remotely controlled demolition unit adapted to be self-propelledto its objective and adapted to fire scuttling and main explosivecharges carried thereby under remote control of an operator of the unit,the combination of normally unarmed means under control of the operatorof the unit for ring the scuttling and main explosive charges inpredetermined time spaced relation when the unit reaches its objective,means controlled by said normally unarmed rneansV for rendering thepro-V pelling means of the unit inoperative and thereafter invariablyfiring the scuttling charges, and meansunder control of the operator oftheV unit for arming said 'normally unarmed means as the unit approachesits obcircuits for tiring said scuttling and main explosive charges inpredetermined sequence or for firing either the main or scuttlingcharges selectively under control of the operator of the unit when theunit reaches its objective, means controlled. by oneof said normallyunarmed control circuits for rendering the ,propelling means of the unitinoperative and thereafter invariably firing the Yscuttling charges, anda circuit under' control of the operator of Vthe unit for arming saidnormally unarmed circuits as the unit approaches its objective.

4. In a remotely controlled demolition unit adapted to be self-propelledto its objective and adapted to re scuttling and .main explosive chargescarried thereby under remote control of an operator of the unit, Vthecombination of a first rotary timing means adaptedk to be set intooperation under control of the operator of the unitv whenrthe unitreaches its objective, a second rotary timing means adapted to be setinto operation as the first'rotary timing means is operated, meanscontrolled by the second rotarytiming means for firing the scuttlingcharges within a relatively short interval of time after operationy ofthe second rotary timing means is initiated thereby to scuttle the unit,and means controlled by the iirst rotary timing means for firing themain charge within a relatively long period of time after operation ofthe iirstk rotary means is initiated.

5. In a remotely controlled demolition unit adapted to beself-propelledy to its objective and adapted to fire scuttling and mainexplosive charges carried thereby under remote control of an operator ofthe unit, the

combination of a first 'rotary timing means adapted to be set intooperation under control of the Operator of the unit as the unitapproaches its objective, second, third and fourth rrotary timing means,means adapted to be operated by said rst'rotary timing means as theV rsttiming means operates for rendering s aid second, third and fourthrotary timing means effective to be set in operation selectively undercontrol of the operator of the unit when the unit reaches its objective,meanscontrolled by each of said second and third rotary means for firingsaid main charge within relatively short-and lo'ng intervals of timerespectively after operation of said second and third means isinitiated, means controlled by said fourth rotary means for firing saidscuttling charges within a relatively short interval of time afteroperation ofthefourth means is initiated, and means controlled byv saidthirdfrotary means for initiating operation of the fourth rotary meanswhen operation of the third rotary means is initiated.

6. In a remotely controlled demolition unit adapted to be self-propelledto its objective and adapted to re scuttling and main explosive chargescarried thereby under remote control of an operator of the unit, thecombination of a first rotary timing means adapted to be set intooperatiming means, means adapted to be operated by said iirst rotarytiming means as the first timing means operates for rendering saidsecond, thid and fourth rotary timing means eective to be set inoperation selectively under control of the operator of the unit when theunit reaches its objective, means controlled by each of said second andthird rotary means for firing said detonating means within relativelyshort and long intervals of time respectively after operation ofsaid'second and third means is initiated, means controlled by saidfourth rotary means for tiring said scuttling charges within arelatively short interval of time after operation of the fourth means isinitiated, and means controlled by said third rotary means forinitiating operation of the fourth rotary means when operation of thethird rotary means is initiated.

7. In a remotely controlled demolition unit adapted to be self-propelledto its objective and adapted to tire scuttling and main explosivecharges carried thereby under remote control of an operator of the unit,the combination of a iirst rotary timing means adapted to be set intooperation under control of the operator of the unit as the unitapproaches its objective, second, third and fourth rotary timing means,means adapted to be operated by said iirst rotary timing means as thefirst timing means operates for rendering said second, third and fourthrotary timing means effective to be set in operation selectively undercontrol of the operator of the unit when the unit reaches its objective,means controlled by each of said second and third rotary means forfiring said main charge within relatively short and long intervals oftime respectively after operation of said second and third means isinitiated, means controlled by said fourth rotary means for tiring saidscuttling charges within a relatively short interval of time afteroperation of the fourth means is initiated, means controlled by saidthird rotary means for initiating operation of the fourth rotary meanswhen operation of the third rotary means is initiated, and meanscontrolled by the fourth rotary timing means for disabling thepropelling means of the unit as the fourth rotary means operates.

8. In a remotely controlled demolition unit adapted to be self-propelledto its objective and adapted to fire scuttling and main explosivecharges carried thereby under remote control of an operator of the unit,the combination of a first rotary timing means adapted to be set intooperation under control of the operator of the unit as the unitapproaches its objective, detonating means adapted to fire the maincharge when an operative firing relation is established therewith and asthe detonating means is fired, means adapted to be operated by saidfirst timing means as the rst timing means operates for establishingsaid operative iiring relation between said detonating means and saidmain charge, second, third and fourth rotary timing means, means adaptedto be operated by said first rotary timing means as the first timingmeans operates for rendering said second, third and fourth rotary timingmeans effective to be set in operation selectively under control of theoperator of the unit when the unit reaches its objective, meanscontrolled by each of said second and third rotary means for firing saiddetonating means within relatively short and long intervals of timerespectively after operation of said second and third means isinitiated, means controlled by said fourth rotary means for tiring saidscuttling charges within a relatively short interval of time afteroperation of the fourth means is initiated, means controlled by saidthird rotary means for initiating operation of the fourth rotary meanswhen operation of the third rotary means is initiated, and meanscontrolled by the fourth rotary timing means for disabling thepropelling means of the unit as the fourth rotary means operates.

9. In a demolition unit adapted to be self-propelled to its objectiveand adapted to fire scuttling and main explosive charges, carriedthereby under remote control of an operator of the unit, the combinationof a pair of contacts adapted to be yieldably urged into engagement witheach other and a rotatable element therefor adapted to maintainthecontacts positively disengaged until the element is rotated to apredetermined position, means under control of the operator of the unitfor causing said element to rotate to said predetermined position as theunit approaches its objective thereby to close the contacts, and meansrendered effective upon closure of said contacts to iire said scuttlingand main charges in predetermined sequence or to fire either of saidscuttling or main charges selectively under control of the operator ofthe unit when the unit has reached its objective.

l0. In a remotely controlled demolition unit adapted to beself-propelled to its objective and adapted to fire scuttling andmain-explosive charges carried thereby underremote control of anoperator of the unit, the combination of first, second, third and fourthpairs of contacts and iirst, second, third and fourth rotatable elementsassociated respectively therewith and adapted to maintain the contactsindividual thereto positively disengaged until each of the elements hasbeen rotated to a predetermined position, eachof said pairs of contactsbeing yieldably urged into engagement with each other whereby each pairof the contacts is closed as the element individual thereto moves intoits predetermined position, means under control of the operator of theunit for imparting rotary movement to the first element and forterminating the rotary movement at said predetermined position thereofthereby closing said first pair of contacts, means controlled by thefirst pair of contacts for causing rotary movement to be imparted to thesecond, third and fourth elements selectively under control of theoperator of the unit when the first pair of contacts are closed, meanscontrolled by the second pair of contacts for tiring the main chargewhen the second pair of contacts close as the second element reaches itspredetermined position, means controlled by the third pair of contactsfor firing the main charge when the third pair of contacts close as thethird element reaches its predetermined position, and means controlledby the fourth pair of contacts for firing the scuttling charges when thefourth pair of contacts close as the fourth element reaches itspredetermined position.

11. In a remotely controlled demolition unit having a plurality ofexplosive scutting charges and a main explosivev charge, the combinationof a first electroresponsive detonating deviceassociated with the maincharge and normally maintained out of tiring relation therewith, aplurality of electroresponsve detonating devices respectively associatedwith said plurality of scuttling charges, a normally unarmed controlcircuit adapted to re said plurality of electroresponsve detonatingdevices thereby to tire the scuttling charges, a normally unarmedcontrol circuit adapted to tire said first electroresponsve detonatingmeans thereby to fire the main charge, and a control circuit havingmeans under control of the operator of the unit for establishing anoperative tiring relation between the first electroresponsve device andthe main charge and for arming said other control circuits, said maincharge firing control circuit having rotary timing means adapted to beset into operation selectively under control of an operator of the unitand adapted to tire the iirst detonating device to iire the main chargewithin a predetermined period of time after operation thereof isinitiated, and said scuttling charge tiring control circuit havingrotary timing means adapted to be set in operation selectively undercontrol of the operator of the unit or in response to operation of therotary timing means of the main charge firing control circuit andadapted to fire the plurality of detonating devices to fire thescuttling charges within a predetermined period of time after operationthereof is initiated.

l2. In a remotely controlled demolition unit adapted to beself-propelled to its objective and adapted to tire scuttling and maincharges carried thereby under remote control of an operator of the unit,the combination of a rotary timing device, means including a relayadapted to set said timing means in operation under control of theoperator of the unit when the unit reaches :its objective,

means controlled by the rotary timing device for firing the scuttlingcharges within a predetermined period of time after the timing device isoperated thereby to scuttle the unit, and means controlled by saiddevice for firing the main charge within a predetermined period of timeafter the unit is scuttled.

' 11i. In a remotely controlled demolition unit adapted to beself-propelled to its objective and adapted to fire scuttling and mainexplosive charges carried thereby under remote control of an operator ofthe unit, the combination of a first rotary timing means adapted to beset into operation under control of the operator of the unit as the unitapproaches its objective, second, third and fourth rotary timing meanseach having a relay ladapted to initiate operation of the timing meansindividual thereto as the relay operates, means adapted to be operatedVby said first rotary timing means as the rst timing means operates forrendering said relays eiective to he operated selectively under controlof the operator of the lunit when the unit reaches its objective, meanscon` trolled by each of said second and third rotary means for tiringsaid main charge within relatively short and long intervals of timerespectively after operation of saidV second and third means isinitiated, means controlled by said. fourth rotary means forfiring saidscuttling charges' within a relatively short interval of time afteroperation of the fourth means is initiated, and means controlled for, amovable obstructing device interposed between said charge and detonatingdevice and movable from an initial position preventing'an operativefiring connection therebetween into an armed position providing saidring connection, means for yieldably urging saidobstructing device fromthe initial position to the armed positiony thereof, electroresponsivemeans effective until'operated to releasably retain said obstructingdevice in said initial position thereof, a plurality of explosivescuttling charges and a plurality of electroresponsive detonatingdevices individual thereto, first, second, third and fourth pairs ofcontacts, each of said pairs of contacts having 'the contacts thereofyieldably urged into engagement `with each other,` rst, second, thirdand fourth rotatable Aelements individual to said pairs of contacts andeach so constructed and arranged intermediate the contacts individualthereto as to maintain the contacts positively disengaged yuntil theelement is rotated from an initial position to a predetermined position,circuit means including an electroresponsive rotary timing devicearranged to be operated under control of the operator of the unit formoving said rst Velement to its predetermined position when the timingdevice is operated, circuit means controlled by said timing device foroperating said electroresponsive retaining means as said rst elementmoves from its initial position to its predetermined position, circuitmeans controlled by said first pair of contacts for causing rotarymovement to be imparted to said second, thirdand fourth elementsselectively under control of the operator of the unit when ythe firstpair of contacts are closed, circuit determined position.

References Cited in the file of this patent UNITED STATES PATENTS693,597 Gardner Feb. 18, 1902` 711,743 Shoemaker Oct. 21, 1902 719,405Wilson Jan. 27, 1903 1,177,280 Scott Mar. 28, 1916 1,495,020 Hall May20, 1924 1,541,790 Cheley et al. June l16, 1925 1,623,475 Hammond Apr.5, 1927 2,146,562 Cameron-et al. Feb. 9, 1939 2,248,237 Fulton Iuly 15,V1941 2,389,288 Anderson Nov. 20, 1945

